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A nonlocal gravity model with a function $f(\Box^{-1} R)$, where $\Box$ is the d'Alembert operator, is considered. The algorithm, allowing to reconstruct $f(\Box^{-1} R)$, corresponding to the given Hubble parameter and the state parameter…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-18 Sergey Yu. Vernov

A nonlocal gravity model which does not assume the existence of a new dimensional parameter in the action and includes a function $f(\Box^{-1} R)$, with $\Box$ the d'Alembertian operator, is studied. By specifying an exponential form for…

High Energy Physics - Theory · Physics 2013-07-24 Emilio Elizalde , Ekaterina O. Pozdeeva , Sergey Yu. Vernov , Ying-li Zhang

We investigate the cosmological dynamics of nonlocally corrected gravity involving a function of the inverse d'Alembertian acting on the Gauss-Bonnet term. Casting the dynamical equations in local form, we derive the reconstruction…

General Relativity and Quantum Cosmology · Physics 2020-03-12 Emilio Elizalde , Ekaterina O. Pozdeeva , Sergey Yu. Vernov

A nonlocal gravity model, which does not assume the existence of a new dimensional parameter in the action and includes a function $f(\Box^{-1} R)$, with $\Box$ the d'Alembertian operator, is considered. The model is proven to have de…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-08 E. Elizalde , E. O. Pozdeeva , S. Yu. Vernov

We employ the superpotential technique for the reconstruction of cosmological models with a non-minimally coupled scalar field evolving on a spatially flat Friedmann-Robertson-Walker background. The key point in this method is that the…

General Relativity and Quantum Cosmology · Physics 2013-03-08 A. Yu. Kamenshchik , A. Tronconi , G. Venturi , S. Yu. Vernov

A non-local gravity model, which includes a function $f(\Box^{-1} R)$, where $\Box$ is the d'Alembert operator, is considered. For the model with an exponential $f(\Box^{-1} R)$ de Sitter solutions are explored, without any restrictions on…

General Relativity and Quantum Cosmology · Physics 2019-10-30 E. Elizalde , E. O. Pozdeeva , S. Yu. Vernov

We consider nonlocal modification of the Einstein theory of gravity in framework of the pseudo-Riemannian geometry. The nonlocal term has the form $\mathcal{H}(R) \mathcal{F}(\Box)\mathcal {G}(R)$, where $\mathcal{H}$ and $\mathcal{G}$ are…

High Energy Physics - Theory · Physics 2015-08-25 Ivan Dimitrijevic , Branko Dragovich , Jelena Grujic , Zoran Rakic

In this paper we consider modification of general relativity extending $R - 2 \Lambda$ by nonlocal term of the form $\sqrt{R-2\Lambda}\, \mathcal{F}(\Box)\, \sqrt{R-2\Lambda} ,$ where $\mathcal{F}(\Box)$ is an analytic function of the…

General Relativity and Quantum Cosmology · Physics 2019-09-04 I. Dimitrijevic , B. Dragovich , A. S. Koshelev , Z. Rakic , J. Stankovic

This paper is devoted to a simple nonlocal de Sitter gravity model and its exact vacuum cosmological solutions. In the Einstein-Hilbert action with $\Lambda$ term, we introduce nonlocality by the following way: $R - 2 \Lambda =…

General Relativity and Quantum Cosmology · Physics 2022-12-28 Ivan Dimitrijevic , Branko Dragovich , Zoran Rakic , Jelena Stankovic

In this paper, we investigate a nonlocal modification of general relativity (GR) with action $S = \frac{1}{16\pi G} \int [ R- 2\Lambda + (R-4\Lambda) \, \mathcal{F}(\Box) \, (R-4\Lambda) ] \, \sqrt{-g}\; d^4x ,$ where $\mathcal{F} (\Box) =…

General Relativity and Quantum Cosmology · Physics 2020-06-30 I. Dimitrijevic , B. Dragovich , A. S. Koshelev , Z. Rakic , J. Stankovic

We investigate the different energy conditions in nonlocal gravity, which is obtained by adding an arbitrary function of d'Alembertian operator, $f(\Box^{-1})$, to the Hilbert- Einstein action. We analyze the validity of four different…

General Relativity and Quantum Cosmology · Physics 2019-10-15 M. Ilyas

We present a new approach of the reconstruction method based on the use of the cosmic parameters instead of a time law for the scale factor. This allows the derivation and analysis of a set of new non-trivial cosmological solutions for…

General Relativity and Quantum Cosmology · Physics 2015-05-18 Sante Carloni , Rituparno Goswami , Peter K. S. Dunsby

The cosmological dynamics of a non-locally corrected gravity theory, involving a power of the inverse d'Alembertian, is investigated. Casting the dynamical equations into local form, the fixed points of the models are derived, as well as…

General Relativity and Quantum Cosmology · Physics 2018-11-06 E. Elizalde , S. D. Odintsov , E. O. Pozdeeva , S. Yu. Vernov

We consider some cosmological aspects of nonlocal modified gravity with $\Lambda$ term, where nonlocality is of the type $R \mathcal{F}(\Box) R$. Using ansatz of the form $\Box R = r R +s,$ we find a few a(t) nonsingular bounce cosmological…

General Relativity and Quantum Cosmology · Physics 2015-08-20 I. Dimitrijevic , B. Dragovich , J. Grujic , Z. Rakic

A modified form of non-locally corrected theory of gravity is investigated in the context of cosmology and the Newtonian limit. This form of non-local correction to classic Einstein-Hilbert action can be locally represented by a…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Dao-Jun Liu , Bin Yang , Xing-Hua Jin

We apply Gaussian processes and Hubble function data in $f(T)$ cosmology, to reconstruct for the first time the $f(T)$ form in a model-independent way. In particular, using $H(z)$ datasets coming from cosmic chronometers as well as from the…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-09 Yi-Fu Cai , Martiros Khurshudyan , Emmanuel N. Saridakis

We discuss some main aspects of theories of gravity containing non-local terms in view of cosmological applications. In particular, we consider various extensions of General Relativity based on geometrical invariants as $f(R, \Box^{-1} R)$,…

General Relativity and Quantum Cosmology · Physics 2022-01-13 Salvatore Capozziello , Francesco Bajardi

A non-local modified gravity model with an analytic function of the d'Alembert operator is considered. This model has been recently proposed as a possible way of resolving the singularities problem in cosmology. We present an exact bouncing…

High Energy Physics - Theory · Physics 2012-09-18 Alexey S. Koshelev , Sergey Yu. Vernov

A non-local modified gravity model with an analytic function of the d'Alembert operator that has been proposed as a possible way of resolving the singularities problems in cosmology is considered. We show that the anzats that is usually…

General Relativity and Quantum Cosmology · Physics 2015-01-09 Alexey S. Koshelev , Sergey Yu. Vernov

We consider a new modified gravity model with nonlocal term of the form $R^{-1} \mathcal{F}(\Box) R. $ This kind of nonlocality is motivated by investigation of applicability of a few unusual ans\"atze to obtain some exact cosmological…

High Energy Physics - Theory · Physics 2014-11-20 Ivan Dimitrijevic , Branko Dragovich , Jelena Grujic , Zoran Rakic
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